The present invention is directed to devices, methods and systems for administering localized radiation to vessels, lumens, or cavities of a body, such as cardiovascular tissue, to treat restenosis and other conditions.
In the medical field, doctors and scientists strive to find less invasive ways to treat patients. By using treatments that are less intrusive to the body, doctors can greatly reduce the stress on the patient""s systems and exposure to infection. For example, laparoscopic techniques enable physicians to explore the interior of the body and perform surgery through a small opening in the skin. Less intrusive medical techniques are extremely beneficial when applied to cardiovascular diseases.
Cardiovascular diseases affect millions of people, often causing heart attacks and death. One common aspect of many cardiovascular diseases is stenosis, or the thickening of the artery or vein, decreasing blood flow through the vessel. Angioplasty procedures have been developed to reopen clogged arteries without resorting to a bypass operation. However, in a large percentage of cases, arteries become occluded again after an angioplasty procedure. This recurrent thickening of the vessel is termed restenosis. Restenosis frequently requires a second angioplasty and eventual bypass surgery. Bypass surgery is very stressful on the patient, requiring the chest to be opened, and presents risks from infection, anesthesia, and heart failure.
Effective methods of preventing or treating restenosis could benefit millions of people. One treatment for restenosis that has been attempted is beta-irradiation of the vessel wall by positioning radioactive isotopes in the vessel at the site of the restenosis. However, the depth of the penetration of the radiation is difficult to control with this method. The depth of the radiation is determined by the type of the radio-isotope used. The radioactive source will also irradiate other healthy parts of the body as it is brought to the site to be treated. Another disadvantage is that medical personnel must take extensive precautions when handling storing, and disposing the radioactive material.
Less intrusive techniques are also extremely beneficial when applied to the esophagus. Tens of millions of Americans suffer from gastroesophageal reflux disease (GERD). GERD is characterized by a backward flow of the stomach and duodenal contents into the esophagus. These conditions result when the valve at the junction between the esophagus and the stomach does not function properly. When this occurs frequently, it is termed chronic GERD or reflux esophagitis. The symptoms of this condition are dyspepsia, or discomfort in the esophagus after meals, burning chest, upper abdominal pain, sour taste, and regurgitation.
Medical research has revealed that the acidic stomach contents cause anatomic abnormalities of the epithelium, or lining, of the esophagus during reflux. The cell type of the epithelium of the esophagus changes from a squamous, or circular-shaped cell, to a columnar, or rectangular-shaped, cell type. This cellular damage of the epithelium is termed Barrett""s esophagus.
Barrett""s esophagus is a precursor for cancer of the gastroesophageal system. Barrett""s-associated malignancies strike approximately 10,000 people per year. There is a high rate of progression from reflux disease to Barrett""s esophagus. In fact, 90 percent of patients with reflux symptoms who have an endoscopic examination show anatomic abnormalities of the epithelium.
Diagnosis of cancer in Barrett""s esophagus ordinarily leads to removal of the diseased segment of the esophagus. However, an effective treatment of Barrett""s disease could prevent the progression to cancer and could therefore reduce the need for this painful and drastic procedure. An effective treatment for Barrett""s esophagus could improve the lives of many people. Ultrasound and argon-ion plasma treatments have been suggested to treat Barrett""s esophagus, but these techniques are in early experimental stages and have not been proven effective. It is believed that photodynamic therapy is also a possibility.
Many other disorders could be treated with small, effective medical devices capable of accessing the interior of the body. For example, one disorder of the gastrointestinal system is pyloric strictures. Pyloric strictures occur in the pylorus, or distal aperture of the stomach. The pylorus is surrounded by a strong band of circular muscle, through which the stomach contents are emptied into the duodenum. Pyloric strictures can be subjected to dilatation to open the pylorus passage. However, the pylorus frequently thickens in response to the dilatation. Repeated dilatation has been used to treat pyloric strictures, but has not proven to be an effective long-term solution. There is a need for treatments to prevent this recurrent thickening of the pylorus.
Thus, there is a need for miniature devices and effective methods to treat the interior of the body with minimal intrusion. Effective, less invasive techniques for treating stenosis and restenosis of a lumen, treating GERD, and treating pyloric strictures are especially needed.
Recently, X-ray radiation has been realized to provide a very promising way to treat these types of conditions. Ionizing radiation penetrates to the first layers of cells on the surface of the passage or lumen. This radiation induces apoptosis, or programmed cell death.
Apoptosis differs from another type of cell death, necrosis. In apoptosis, a disruption in the gene structure of the cell results in the cell failing to replicate, and in some cells, results in an induced cell death where the contents of the cell are utilized by adjacent cells. Cell death by apoptosis therefore reduces inflammation and the biochemical results of inflammation, as compared to necrosis, which results in scarring and thickening of the surface cells.
X-ray device radiation of the esophagus may be used to treat Barrett""s esophagus by inducing apoptosis in the abnormal cells of the epithelium. The escalation of this condition to cancer may be reduced. X-ray radiation can also be used for preventing the thickening of the pylorus after dilatation of pyloric strictures.
X-ray radiation has been found to reduce the occurrence of restenosis when X-ray radiation is applied to area of a blood vessel where an angioplasty or other expansion of the vessel has taken place. In coronary applications, it is desirable to have the X-ray radiation penetrate into the adventitia tissue. The advantages and disadvantages of X-ray radiation penetration into the cardiac muscle tissue are still being investigated. Further, it is desirable to deliver X-ray radiation with a peak energy of about 6-15 kiloelectron volts (keV) in coronary applications. The peak energy may also be 8-10 kiloelectron volts.
X-ray treatment devices for these types of applications must be small and flexible enough to fit inside the vessels and passages, yet have enough rigidity and structural integrity so that they can be advanced a distance through the body and contain the advanced treatment device. In the case where an X-ray device is to be delivered through vessels and passages, there is also the additional complication of providing a high voltage to the treatment device while inside the body. Using the X-ray device may generate heat inside the patient, and the delivery system should prevent any heat from damaging surrounding tissue. If the treatment area is large enough that it cannot be treated from one point inside the body, the treatment device may have to be moved across the treatment area during therapy.
Thus there is a need for delivery formats to be used for example in connection with an X-ray device for emitting localized radiation inside a patient""s body. The delivery formats need to include devices and methods that deliver the treatment device reliably to the treatment site, treat the site uniformly and deliver a predictable dose, while being easy to use and avoiding invasive steps in the treatment.
The invention relates to a device for X-ray treatment in a passage of a body, a method for positioning an X-ray emitter in a passage of a body, a method for exposing a length of a treatment area to X-ray radiation and a method for automatically moving an X-ray catheter. Further, the invention relates to a valve adapter for allowing fluid flow under pressure to the interior of a sheath and allowing movement of the cable relative to the sheath. The invention further relates to a catheter pullback assembly and a treatment system.
A device suitable for X-ray treatment in a passage within a body of a patient is described, including a sheath that has a wall, a proximal end, and a distal end, where the sheath wall defines a primary lumen longitudinally through the sheath, and an X-ray emitter coupled to a cable, positionable within the primary lumen so that the X-ray emitter is near the distal end of the sheath.
The device may further include a stylet defining a stylet lumen, wherein the stylet is positionable within the primary lumen.
The sheath of the device may define a parking lumen adjacent to a portion of the primary lumen. The parking lumen has a proximal end and a distal end and the distal end of the parking lumen has an opening to the primary lumen and the proximal end of the parking lumen has an opening to the exterior of the sheath.
The sheath may alternatively define a parking lumen adjacent to a portion of the primary lumen, including openings to the exterior of the sheath. The X-ray emitter may be moveable within the primary lumen or fixed within the lumen near the distal end of the sheath.
The device may also include a guide wire segment coupled to the distal end of the sheath. The X-ray emitter may be movable within the primary lumen or fixed within the primary lumen near the distal end of the sheath.
The invention also provides a method for positioning an X-ray emitter at a treatment area in a passage within a body of a patient. The method includes the step of moving a guide wire, having a proximal end and a distal end, through the passage so that the distal end is distal to the treatment area, advancing a sheath over the proximal end of the guide wire, where the sheath has a proximal end, a distal end and a primary lumen extending longitudinally through the sheath and receiving the guide wire so that the distal end of the sheath is distal to the treatment site, withdrawing the guide wire from the primary lumen, and placing the X-ray emitter coupled to a cable in the primary lumen so that the X-ray emitter is positioned distal to the treatment site.
Also described is an alternative method for positioning an X-ray emitter at a treatment area in a passage within a body of a patient. The method includes moving a guide wire having a proximal end and a distal end, through the passage so that the distal end is distal to the treatment area, advancing the sheath, defining a parking lumen adjacent to a portion of the primary lumen and having a proximal end and a distal end, the distal end of the parking lumen having an opening to the primary lumen and the proximal end of the parking lumen having an opening to the exterior of the sheath, where the sheath is advanced by inserting the guide wire into the distal end of the primary lumen and into the parking lumen so that the distal end of the sheath is distal to the treatment area, and placing the X-ray emitter at the distal end of the sheath within the primary lumen.
Another method for positioning an X-ray emitter is described where the sheath defines a parking lumen adjacent to a portion of the primary lumen. The parking lumen has a proximal end and a distal end that have openings to the exterior of the sheath, the sheath being advanced so that a distal end of the sheath is distal to the treatment area by placing the guide wire into the parking lumen, and placing the X-ray emitter at the distal end of the sheath within the primary lumen.
An alternative method for positioning an X-ray emitter includes a guide wire segment extending beyond the distal end of the sheath, so that the distal end is distal to the treatment area.
The present invention also describes a method of exposing a length of treatment area in a patient to X-ray radiation, where the X-ray emitter is coupled to a connector at the distal end of the connector. The method includes providing a sliding carriage mounted on a body, the carriage being attached to a proximal end connector and attached to an actuator and controlling the actuator and connector to apply X-ray radiation across the length of the treatment area by moving the X-ray emitter.
The present invention also describes a method of moving a catheter inside a sheath automatically across a length of a treatment area, while the distal end of the catheter is positioned inside a patient. The method includes providing a pullback assembly having a body and a sliding carriage, where the carriage is attached to the proximal end of the cable support tube and to an actuator, and the body is attached to the proximal end of the sheath, and automatically controlling the actuator to move the carriage.
A bellows valve adapter for allowing fluid flow around an X-ray emitter and permitting positioning of the X-ray emitter is also part of the present invention. The adapter includes a catheter sheath having a distal and a proximal end, a cable support tube, having a distal and a proximal end, where the distal end of the support tube and a portion of the support tube are inside the catheter sheath, and a bellows being a collapsible tube having a first and a second end, where the first end of the bellows is connected to the proximal end of the catheter sheath and second end is connected to the proximal end of the cable support tube.
A hemostasis valve adapter for allowing fluid flow around an X-ray emitter and permitting positioning of the X-ray emitter is provided. The valve adapter includes a catheter sheath, a cable support tube, where the distal end of the support tube and a portion of the support tube are inside the catheter sheath, and a seal device on the proximal end of the catheter sheath for sealing between the catheter sheath and the cable support tube, where the cable support tube is movable through the seal.
A catheter pullback assembly for retracting or advancing an X-ray emitter coupled to a cable is provided. The cable and the X-ray emitter may be positionable inside a catheter sheath, and the cable and X-ray emitter are movable relative to the catheter sheath. The assembly includes a body, a carriage mounted on the body, where the carriage is slidable with respect to the body, a distal pullback adapter is attached to a proximal end of the catheter sheath, where the adapter is mounted on the body, and a proximal pullback adapter, attached onto the cable, where the pullback adapter is mounted on the carriage.
A system for X-ray treatment in a passage within a body of a patient is also provided. The system includes a sheath, a cable support tube, where the distal end of the support tube and a portion of the support tube are inside the sheath, and an X-ray emitter coupled to a cable. The system also includes means for allowing fluid flow around the X-ray emitter and permitting positioning of the X-ray emitter, a cable pullback assembly having a body, a carriage mounted on the body the carriage slidable with respect to the body, distal pullback adapter sealed onto a proximal end of the sheath, where the distal pullback adapter is mounted on the body, and a proximal pullback adapter, sealed onto the cable, where the proximal pullback adapter is mounted on the carriage.
A system for controlling an X-ray emitter to deliver X-ray radiation to a treatment area within a patient is also provided. The system includes a pullback assembly having a body, a sliding carriage mounted on the body, a pullback adapter for the catheter luge mounted on the body, and a pullback adapter for the cable support tube mounted on the carriage. The system also includes a catheter sheath attached onto the distal pullback adapter, and the X-ray catheter includes the X-ray emitter operatively coupled to a connector, where the X-ray catheter is positioned within the catheter sheath lumen, and a control unit coupled to the connector and to the carriage, being capable of applying voltage to the connector and comprising a power source, an actuator for the pullback assy and a central processor.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, and its advantages, and the objects obtained by its use reference should be made to the accompanying drawings and descriptive matter, which form a further part hereof, and in which there is illustrated and described preferred embodiments of the invention.